In general, a compressor is an instrument to compress a gas such as a coolant. There are several types of compressors including a rotary compressor, a reciprocating compressor, a scroll compressor.
The general compressor includes a closed container having a space therein, an electronic mechanism unit installed inside the closed container and generating a driving force, and a compression mechanism unit for receiving the driving force from the electronic mechanism unit and compressing gas.
FIG. 1 is a sectional view of the rotary compressor in accordance with a conventional art.
As shown in FIG. 1, in the rotary compressor, as a rotor 2 of an electronic mechanism unit (M) installed in a closed container 1 is rotated, a rotational shaft 3 press-fit in the rotor 2 is rotated. According to the rotation of the rotational shaft 3, a rolling piston 5 inserted in an eccentric part 3a of the rotational shaft 3 positioned in the compression space (P) of a cylinder 4 linearly contacts the inner circumferential surface of the compression space (P) of the cylinder and also linearly contacts a vane (not shown) inserted at one side of the cylinder 4 to divide the compression space (P) into a high pressure portion and a low pressure portion, so as to be rotated in the cylinder compression space (P) to compress a coolant gas sucked into a suction hole 4a formed at the cylinder 4 and discharge it through a discharge passage 4b. These processes are repeatedly performed.
FIG. 2 is a sectional view of a reciprocating compressor in accordance with a conventional art.
As shown in FIG. 2, in the reciprocating compressor, as a rotor 12 of an electronic mechanism unit (M) mounted in a closed container 11 is rotated, a crank shaft 13 press-fit to the rotor 12 is rotated. According to the rotation of the crank shaft 13, a piston 14 coupled to an eccentric part 13a of the crank shaft 13 makes a linear and reciprocal movement in the compression space (P) of the cylinder 15, to compress a coolant gas sucked through a valve assembly 16 coupled to the cylinder 15 and discharge the coolant gas through the valve assembly 16. These processes are repeatedly performed.
FIG. 3 is a sectional view of a scroll compressor in accordance with a conventional art.
As shown in FIG. 3, in the scroll compressor, as a rotor 22 of the electronic mechanism unit (M) mounted in the closed container 21 is rotated, a rotational shaft 23 having an eccentric part 23a press-fit to the rotor 22 is rotated. According to the rotation of the rotational shaft 23, an orbital scroll 24 connected to the eccentric part 23a of the rotational shaft 23 is engaged with a fixed scroll 25 and revolved. Then, a plurality of compression pockets formed by wraps 24a and 25a having an involute curved line form respectively formed at the orbital scroll 24 and the fixed scroll 25 are reduced in size, to suck, compress and discharge a coolant gas continuously. This processes are repeatedly performed.
The structural and reliability aspects of the rotary compressor, the reciprocating compressor and the scroll compressor of the conventional art each operated in a compression mechanism as described above will now be described.
First, referring to the rotary compressor, in the structural aspect, since a plurality of balance weights 6 are used coupled to the rotor 2 to rotational balance between the rotational shaft 3 having the eccentric part 3a, the rolling piston 5 press-fit to the eccentric part 3a and the eccentric part 3a, there are many constructional components and its structure is somewhat complicated. In the aspect of a reliability, since the eccentric part 3a and the rolling piston 5 formed at the rotational shaft 3 are eccentrically rotated, a big vibration noise is generated.
Referring to the reciprocating compressor, in its structural aspect, the balance weight 13b is used for a rotational balance between the crank shaft 13 having an eccentric part 13a, the piston 14 coupled to the crank shaft 13 and the crank shaft eccentric part 13a, resulting in that there are numerous components and its structure is complicated.
In addition, in the aspect of a reliability, since the eccentric part 13a formed at the crank shaft 13 is eccentrically rotated, a vibration noise is generated, and since the valve assembly 16 is operated in sucking and discharging, the noise in sucking and discharging is made big.
Referring to the scroll compressor, in the aspect of its structural aspect, the balance weight 26 is used for a rotational balance between the rotational shaft 23 having the eccentric part 23a, the orbital scroll 24 having a wrap formed in an involute curve form, the fixed scroll 25 and the eccentric part 23a, resulting in that there are many components and its structure is complicated. In addition, it is difficult to process the orbital scroll 24 and the fixed scroll 25.
In addition, in the aspect of reliability, a vibration noise is generated due to the turning movement of the orbital scroll 24 and the eccentric movement in the eccentric part 23a of the rotational shaft.
As stated above, in case of the rotary compressor, the reciprocating compressor and the scroll compressor, the compression mechanism unit compresses a gas upon receipt of a rotational force of the electronic mechanism unit. Thus, in order to control the amount of the compressed gas generated in the compressor, the number of rotations of the electronic mechanism unit should be reduced or the electronic mechanism unit should stop rotating, which makes it difficult to accurately control the amount of the compressed gas.
In addition, since the eccentric parts 3a, 13a and 23a are provided at the shaft which is rotated upon receipt of the rotational force from the electronic mechanism unit, the balance weights 6, 13b and 26 are used, causing that a driving force is much consumed, and as the vibration noise is generated in operation, its reliability is degraded. In addition, since the structure is relatively complicate, the assembly productivity is degraded.